1.Make roasted tomato sauce. Preheat oven to 220°C/425°F. Combine ingredients in a large baking dish. Bake about 30 minutes or until onion softens. Blend or process tomato mixture until smooth; season to taste.
2.Meanwhile, coat sardines in flour; shake off excess. Dip sardines into egg, then into combined breadcrumbs and herbs.
3.Heat oil in a large saucepan; deep-fry sardines, in batches, until browned and cooked through. Drain on absorbent paper.